Best Practices for mapping one object to another

Question

My question is, what is the best way I can map one object to another in the most maintainable manner. I cannot change the way the Dto object that we are getting is setup to

Answer 1

This is a possible generic implementation using a bit of reflection (pseudo-code, don't have VS now):

public class DtoMapper
{
    Dictionary properties;

    public DtoMapper()
    {
        // Cache property infos
        var t = typeof(DtoType);
        properties = t.GetProperties().ToDictionary(p => p.Name, p => p);
     }

    public DtoType Map(Dto dto)
    {
        var instance = Activator.CreateInstance(typeOf(DtoType));

        foreach(var p in properties)
        {
            p.SetProperty(
                instance, 
                Convert.Type(
                    p.PropertyType, 
                    dto.Items[Array.IndexOf(dto.ItemsNames, p.Name)]);

            return instance;
        }
    }

Usage:

var mapper = new DtoMapper();
var modelInstance = mapper.Map(dto);

This will be slow when you create the mapper instance but much faster later.